This invention relates to a novel sunflower (Helianthus spp.) plant, to products obtained from the novel plant and to methods of producing the sunflower products.
The cultivated sunflower (Helianthus annuus L.) is a major worldwide source of vegetable oil. In the United States, approximately 4 million acres are planted in sunflowers annually, primarily in the Dakotas and Minnesota.
The very rapid expansion over the last decade of acreage planted in sunflower in the United States is due in part to several important developments in the field of sunflower breeding and varietal improvement. One significant development was the discovery of cytoplasmic male sterility and genes for fertility restoration, a discovery that allowed the production of hybrid sunflowers. The hybrids thus produced were introduced during the early 1970's.
A description of cytoplasmic male sterility (CMS) and genetic fertility restoration in sunflowers is presented by Fick, "Breeding and Genetics," in Sunflower Science and Technology 279-338 (J. F. Carter ed. 1978), the contents of which are incorporated herein by reference.
Sunflower oil is comprised primarily of palmitic, stearic, oleic, linoleic and linolenic acids. While other unusual fatty acids exist in plants, palmitic, stearic, oleic, linoleic, and linolenic acids comprise about 88% of the fatty acids present in the world production of vegetable oils. (Harwood, J. L., Plant Acyl Lipids: Structure, Distribution and Analysis, 4 Lipids: Structure and Function, P. K. Stumpf and E. E. Conn ed. (1988)). Palmitic and stearic acids are saturated fatty acids that have been demonstrated in certain studies to contribute to an increase in the plasma cholesterol level, a factor in coronary heart disease. Vegetable oils high in unsaturated fatty acids, such as oleic and linoleic acids, may have the ability to lower plasma cholesterol according to recent studies. Saturated fatty acids also have higher melting points in general than unsaturated fatty acids of the same carbon number, which contributes to cold tolerance problems in foodstuffs and can contribute to a waxy or greasy mouthfeel. It is also known that food products made from fats and oils having less than about 3% saturated fatty acids will typically contain less than 0.5 gram saturated fat per serving and as a result can be labeled as containing "zero saturated fat" under current labeling regulations. Thus, for a number of reasons it is desirable to produce a sunflower oil having low levels of palmitic and stearic acids and high levels of oleic or linoleic acids.
Prior to the present invention there were no naturally occurring sources of low saturated fatty acid sunflower oils. The generally accepted pathway of fatty acid biosynthesis in plants is that palmitic and stearic acids are the products of the beta ketoacyl-ACP synthetase system which includes three isozymes which are referred to as KAS I, II and III. Stearoyl-ACP acid is desaturated to oleic acid which is esterified to phosphatidylcholine then sequentially desaturated to linoleic and linolenic acids (Stymne, S. and Stobart, A. K., Triacylglycerol Biosynthesis, 9 The Biochemistry of Plants: A Comprehensive Treatise 175-214 (1987) and Stumpf, P. K., Biosynthesis of Fatty Acids in Higher Plants, Oil Crops of the World 38-62 (1989). Previously published research in sunflower has emphasized generally the alteration of the percentage of oleic or linoleic acids. The relative proportions of oleic and linoleic acids can be environmentally influenced (Kinman, M. L., and F. R. Earle., "Agronomic Performance and Chemical Composition of the Seed of Sunflower Hybrids and Introduced Varieties," Crop Science 4:417-420 (1964); Putt, E. D., B. M. Craig, and R. B. Carson. "Variation in Composition of Sunflower Oil from Composite Samples and Single Seeds of Varieties and Inbred Lines, J. Am. Oil Chem. Soc. 46:126-129 (1969); Seiler, G. J., "Variation in Oil and Oil Quality of Wild Annual Sunflower (Helianthus annuus L.) Populations in a Uniform Environment," 10th International Sunflower Conference, Mar. 14-18, 1982. Surfers' Paradise, Australia. p. 212-215; Seiler, G. J., "Effect of Genotype, Flowering Date, and Environment on Oil Content and Oil Quality of Wild Sunflower Seed," Crop Science, 23: 1063-1068 (1983); Seiler, G. J., "Interrelation of Fatty Acids in Oil of Wild Annual Sunflower (Helianthus annuus L.)" Proceedings of the XI International Sunflower Conference. Mar. 10-13, 1985. Mar del Plata, Argentina. p. 529-534; or have been shown in certain genotypes to be inherited in stable manner (Soldatov, K. I., "Chemical Mutagenesis in Sunflower Breeding," International Proceedings, 7th International Sunflower Conference, Krasnodar, U.S.S.R., 27 June-3 July, 1976. International Sunflower Association Vlaardingen, p. 352-357, The Netherlands; Karachenko, L. N., "Genotypic and Phenotypic Mechanisms Ensuring Regulation of Fatty Acid Biosynthesis in Sunflower Seeds," Fiziologiya Rastenii (Russian) 26: 1226-1232 (1979); Fick, G. N., "Breeding and Genetics," Sunflower Science and Technology, Carter, Jack F. (ed.). 1978. Urie, A. L., "Inheritance of Very High Oleic Acid Content in Sunflower," Proc. Sunflower Research Workshop. Bismarck, N.D. 1 February, 1984. National Sunflower Association. Bismarck, N.D. p.9-10; Miller, J. F. and D. C. Zimmerman. "Inheritance of High Oleic Fatty Acid Content in Sunflower." Proc. Sunflower Research Workshop. Fargo, N.D. 26 January, 1983. National Sunflower Association. Bismarck, N.D. p. 10; Urie, A. L., "Inheritance of High Oleic Acid in Sunflower." Crop Science 25:986-989 (1985); Simpson, B. W. and D. L. George, "Potential for Selection of Fatty Acids on a Single Seed Basis in Sunflower (Helianthus annuus L.)." Proceedings of the XI International Sunflower Conference, Mar. 10-13, 1985. Mar del Plata, Argentina. p 791-796; Miller, J. F., D. C. Zimmerman, and B. A. Vick, "Genetic Control of High Oleic Acid Content in Sunflower Oil," Crop Science 27:923-926 (1987); George, D. L., B. W. Simpson, and C. M. McLeod. "Proposed Development of a High Linoleic Acid Sunflower Hybrid." Proceedings of the 12th International Sunflower Conference. Jul. 25-29, 1988. Novi Sad, Yugoslavia. p 448-453; Simpson, B. W., C. M. McLeod and D. L. George. "Selections for High Linoleic Acid Content in Sunflower (Helianthus annuus L.)." Aust. J. of Exper. Agric. 29:233-239 (1989). Recent research has claimed that the level of palmitic acid in sunflower oil can be increased to as high as 40.2% of the total oil (Ivanov, P, D. Petakov, V. Nikolova, and E. Pentchev, "Sunflower Breeding for High Palmitic Acid Content in the Oil." Proceedings of the 12th International Sunflower Conference. Vol II. Jul. 25-29, 1988. Novi Sad, Yugoslavia. p 463-465). The invention disclosed here pertains to the proportion of palmitic and stearic acids relative to the other major fatty acids in sunflower oil: oleic and linoleic acids.